U.S. patent number 4,645,437 [Application Number 06/749,449] was granted by the patent office on 1987-02-24 for scroll compressors with annular sealed high pressure thrust producing member.
This patent grant is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Tsukasa Chiyoya, Makoto Hayano, Tsutomu Ichikawa, Wataru Sakashita.
United States Patent |
4,645,437 |
Sakashita , et al. |
February 24, 1987 |
Scroll compressors with annular sealed high pressure thrust
producing member
Abstract
In a scroll compressor enclosed in a casing and a movable scroll
member is driven eccentrically by an electric motor, a thrust force
created by the compression and applied to the movable scroll member
is cancelled by a high pressure chamber which is provided between a
surface of the movable scroll member and a frame member and
supplied with a pressurized gas delivered from the scroll
compressor. The high pressure chamber is formed into an annular
shape defined by radially inner and outer tapered walls, and
radially inner and outer seal rings having resilience to shrink and
expand respectively are provided in the chamber for preventing
leakage of the gas out of the high pressure chamber.
Inventors: |
Sakashita; Wataru (Fuji,
JP), Chiyoya; Tsukasa (Fuji, JP), Ichikawa;
Tsutomu (Fujinomiya, JP), Hayano; Makoto (Tokyo,
JP) |
Assignee: |
Kabushiki Kaisha Toshiba
(Kawasaki, JP)
|
Family
ID: |
26466098 |
Appl.
No.: |
06/749,449 |
Filed: |
June 27, 1985 |
Foreign Application Priority Data
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Jun 27, 1984 [JP] |
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59-131197 |
Sep 27, 1984 [JP] |
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59-200675 |
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Current U.S.
Class: |
418/55.5;
277/399; 418/57 |
Current CPC
Class: |
F04C
18/0215 (20130101); F04C 27/005 (20130101); F04C
23/008 (20130101) |
Current International
Class: |
F04C
18/02 (20060101); F04C 27/00 (20060101); F04C
23/00 (20060101); F04C 018/04 (); F04C 027/00 ();
F16J 009/08 (); F16J 015/34 () |
Field of
Search: |
;418/55,57,132
;277/81R,81P,82,173,174,216,217 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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57-23793 |
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May 1982 |
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JP |
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57-49721 |
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Oct 1982 |
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JP |
|
Primary Examiner: Vrablik; John J.
Attorney, Agent or Firm: Schwartz, Jeffery, Schwaab, Mack,
Blumenthal & Evans
Claims
What is claimed is:
1. A scroll compressor including a casing, a frame provided in the
casing, a motor and a compressor assembly mounted on opposite sides
of said frame, said compressor assembly having a stationary scroll
member and a movable scroll member respectively having spiral wraps
engaging with each other so that the movable scroll member is
driven by said motor eccentrically around the center of a spiroid
spiral of said stationary scroll member, said movable scroll member
having a planar portion with a lower surface facing said frame,
said stationary scroll member having a peripheral portion secured
to said frame, said scroll compressor further comprising:
an annular member formed adjacent said lower surface and separated
therefrom by a gap, said annular surface having radially outer and
inner walls and a bottom wall for defining an annular high pressure
chamber therebetween, said radially outer and inner walls of said
annular member having internal surfaces tapered radially outwardly
and inwardly from said bottom wall, respectively;
passage means for supplying a portion of a quantity of compressible
fluid delivered from said compressor assembly into said high
pressure chamber for reducing a thrust force applied to said
movable scroll member;
a radially outer resilient seal ring having at least one part of a
radially outer surface thereof tapered to be slidable along said
tapered outer wall of said high-pressure chamber; and
a radially inner resilient sealing ring having at least one part of
a radially inner surface thereof tapered to be slidable along said
tapered inner wall of said high-pressure chamber, said inner and
outer sealing rings sealing said annular high-pressure chamber to
said lower surface of said planar portion by closing said gap, each
of said outer and inner resilient sealing rings including a sealing
surface sealingly contacting said lower surface; and
means for maintaining said seal between said annular high-pressure
chamber and said lower surface upon a change in the width of said
gap, said maintaining means including diameter varying means for
resiliently increasing and decreasing the diameters of said inner
and outer sealing rings when said sealing rings slide along said
respective tapered inner and outer walls.
2. The scroll compressor according to claim 1, wherein said motor
is electric.
3. The scroll compressor according to claim 1, wherein said annular
member is stationary.
4. The scroll compressor according to claim 1 wherein said annular
member is provided separately between said frame and said planar
portion of said movable scroll member so as to be secured to said
frame and said high pressure chamber is formed in said annular
member so as to press said planar portion of said movable scroll
member away from said annular member.
5. The scroll compressor according to claim 1, wherein said
diameter varying means includes a separated portion formed in each
of said seal rings.
6. The scroll compressor according to claim 5, wherein said
separated portion comprises a discontinuity in the circumference of
each respective seal ring.
7. The scroll compressor according to claim 5 wherein said separate
portion is formed between two separate ends of said ring which are
slidable with each other circumferentially so as to vary the
diameter of the seal ring.
8. The scroll compressor according to claim 7 wherein said two
separated ends of said ring are slidable with each other along a
circumferential plane which is selected to pass through an
intermediate portion of the radial thickness of the seal ring.
Description
BACKGROUND OF THE INVENTION
This invention relates to a scroll compressor, and more
particularly to a type thereof wherein sealing of a high pressure
chamber formed between the movable scroll member and the frame can
be substantially improved.
Recently, scroll compressors have been frequently used in
refrigerators and the like. Referring to FIGS. 1 to 5, the scroll
compressor comprises a stationary scroll member 1 and a movable
scroll member 2 respectively having spiral wraps 1a and 2a of
involute or the like configuration. The stationary scroll member 1
and the movable scroll member 2 are engaged with each other with a
predetermined angle (180.degree.) maintained therebetween, so that
a compressing space 3 of a crescent shape is formed between the
wraps 1a and 2a. When the movable scroll member 2 is driven to move
orbitally around the center O.sub.1 of the stationary scroll member
1 while maintaining a predetermined eccentric distance e, the
compressing space 3 is moved toward the center of the spiroid
spiral with the volume of the space 3 being reduced. As a
consequence, the fluid in the compressing space 3 is continuously
compressed and delivered from a central port (not shown) of the
compressor.
FIGS. 3 and 4 illustrate a construction of a compressing element 4
of the scroll compressor, which has been disclosed in our copending
U.S. patent application Ser. No. 655,429 (filed: Sept. 28, 1984).
In the construction, the peripheral portion 5 of the stationary
scroll member 1 is secured to a frame 6 by means of bolts 7 and the
like, while the movable scroll member 2 engaging with the
stationary scroll member 1 is encased in the frame 6 to be freely
revolvable. The movable scroll member 2 has a rear side, which is
opposite to the front side provided with the wrap 2a, supported by
the frame 6 through a high-pressure receiving annular member 9.
The high-pressure receiving annular member 9 is mounted, as shown
in FIG. 4, on a mounting surface 10 of the frame 6, and on the
upper surface 11 of the member 9 is provided a high pressure
chamber 12 for counter-balancing a thrust caused in the compressing
element 4. A fluid passage 14 is formed through a planar portion 13
of the movable scroll member 2 for introducing the fluid extracted
from the compressing space 3, or from the last stage of the
compression, into the high pressure chamber 12. A bearing portion
15 is formed on the rear surface 8 of the movable scroll member 2
to be coupled with an eccentric shaft portion 17 of a crank shaft
16 rotatably supported by the frame 6. As a consequence, when the
crank shaft 16 is rotated, the movable scroll member 2 is revolved
around the center of the wrap 1a of the stationary scroll member 1.
For preventing the rotation of the movable scroll member 2 around
its own axis at this time, an Oldham ring 18 is provided between
the movable scroll member 2 and the frame 6.
In the above described conventional construction of the compressing
element 4, however, the sealing property of the sliding portion
provided between the high-pressure receiving annular member 9 and
the movable scroll member 2 has been comparatively low, and a
relatively large amount of the pressurized fluid may be leaked out
of the high pressure chamber 12. That is, when the pressurized
fluid of a pressure Pd is supplied through the fluid passage 14
into the high-pressure chamber 12, a force Pm pushing the movable
scroll member 2 upward is created in the chamber 12, thereby
providing a gap S of a distance .DELTA.l.sub.1 between the
high-pressure receiving annular member 9 and the rear-side surface
8 of the movable scroll member 2. Because of the provision of the
gap S, the pressure of the fluid in the chamber 12 is reduced, thus
making it difficult to provide a sufficient strength of force
counter-acting against the thrust applied to the movable scroll
member 2. Furthermore, since the leaked fluid has been extracted
from the compressing space 3 or from the last stage of the
compression, leakage of the same reduces the compression efficiency
of the compression element 4.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an improved scroll
compressor wherein the above described difficulties of the
conventional construction can be substantially eliminated.
Another object of the invention is to provide a scroll compressor
wherein sealing rings of a special design are provided in the high
pressure chamber for improving the sealing property of the high
pressure chamber.
According to the invention, there is provided a scroll compressor
of a type comprising a casing, a frame provided in the casing, an
electric motor and a compressor assembly mounted on opposite sides
of the frame, the compressor assembly comprising a stationary
scroll member and a movable scroll member respectively having
spiral wraps engaging with each other so that the movable scroll
member is driven by the electric motor eccentrically around the
center of spiroid spiral of the stationary scroll member, the
movable scroll member having a planar portion on a side thereof
facing the frame, the stationary scroll member having a peripheral
portion secured to the frame, an annular member having radially
outer and inner walls and a bottom wall for defining an annular
high pressure chamber therebetween, and passage means provided for
supplying a part of a compressible fluid delivered from the
compressor assembly into the high pressure chamber for reducing a
thrust force applied to the movable scroll member, wherein the
outer and inner walls of the annular member are provided with
internal surfaces tapered radially outwardly and inwardly from the
bottom wall of the annular member, respectively, and radially outer
and inner seal rings made of a resilient material and each having a
tapered surface are provided in the high pressure chamber such that
the seal rings are slidable relative to the walls of the annular
member with the tapered surfaces of the rings contacting with the
tapered internal surfaces of the radially outer and inner walls of
the annular member.
According to a preferred embodiment of the invention, each of the
seal rings is provided with a separate portion, in which two
separate ends of the ring are slidable with each other along a
circumferential plane which is selected to pass through an
intermediate portion of the radial thickness of the seal ring.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIGS. 1 and 2 are diagrams showing different engaging conditions
between a stationary scroll wrap and a movable scroll wrap;
FIG. 3 is a longitudinal sectional view of a compressor portion of
a conventional scroll compressor;
FIG. 4 is an enlarged sectional view showing one part of FIG.
3;
FIG. 5 is a fragmented perspective view showing a general
construction of a conventional scroll compressor;
FIG. 6 is a longitudinal sectional view showing a compressor
portion of a scroll compressor constituting a preferred embodiment
of this invention;
FIG. 7 is an enlarged sectional view showing one part of FIG.
6;
FIG. 8 is a plan view showing a resilient ring used for this
invention;
FIGS. 9, 10 and 11 are diagrams showing various types of a separate
portion of the resilient ring;
FIG. 12 is a longitudinal sectional view of a resilient ring of an
improved construction according to this invention;
FIGS. 13 and 14 are plan views taken from upper and lower positions
in FIG. 12;
FIGS. 15 and 16 are enlarged views of a separate portion shown in
FIGS. 13 and 14, respectively; and
FIG. 17 is a sectional view showing another embodiment of this
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before entering the description of this invention, a general
construction of a conventional scroll compressor will now be
described in detail with reference to FIG. 5.
As shown in FIG. 5, the scroll compressor 21 comprises a casing 22,
a frame 23 internally secured to the casing 22, an electric motor
24 provided below the frame 23, and a compressor assembly 25
provided above the frame 23. The compressor assembly 25 comprises a
stationary scroll member 26 and a movable scroll member 27 provided
with spiral wraps 26a and 27a which extend downwardly and upwardly
from the two members 26 and 27, respectively. The spiral wraps 26a
and 27a are formed into a similar configuration of, for instance,
involute or the like, and are meshed with each other so that a
closed compressing space 28 of a crescent shape is formed between
the two wraps 26a and 27a. Through a side wall 29 of the casing 22,
a supplying pipe 30 of a gas to be compressed is extended
outwardly, while a delivering pipe 31 for delivering the compressed
gas is extended through the top wall of the casing 22.
The stationary scroll member 26 provided in the casing 22 with the
wrap 26a disposed downwardly is secured at the circumferential
portion 32 thereof to the frame 23 by means of bolts and the like
(not shown). The movable scroll member 27 with the wrap portion 27a
thereof disposed upwardly is received rotatably in an upper part of
the frame 23. A bearing portion 35 is formed to project downwardly
from the lower surface 34 of a planar portion 33 of the movable
scroll member 27. The bearing portion 35 engages with an eccentric
shaft portion 37 of a crank shaft 36 extending vertically upward
and supported rotatably by the frame 23. That is, the movable
scroll member 27 is driven by the crank shaft 36 so that the center
of the member 27 revolves around the center of the stationary
scroll member 26 with a predetermined radius of eccentricity
maintained therebetween. When the movable scroll member 27 thus
revolves around the stationary scroll member 26 in one direction,
the crescent-shaped compressing space 28 formed between the two
wraps 26a and 27a is shifted along the wraps toward the center of
the stationary scroll member 26, while the size of the compressing
space 28 is constantly reduced.
The invention will now be described with reference to FIGS. 6
through 17.
In an embodiment shown in FIG. 6, the peripheral portion 32 of the
stationary scroll member 26 is formed into a flange shape, and is
secured to an upper surface 39 of the frame 23 by means of bolts
42. On the other hand, a high-pressure receiving annular member 40
is provided between the lower surface 34 of the planar portion 33
of the movable scroll member 27 and the frame 23, so that the
movable scroll member 27 is supported by the annular member 40.
More specifically, when the gas is compressed in the compressing
space 28 formed between the two wraps 26a and 27a, a downward
thrust is applied to the movable scroll member 27. For the purpose
of cancelling this thrust, a high pressure chamber 43 is formed on
the upper surface 41 of the annular member 40. The high pressure
chamber 43 is provided in the form of an annular groove 44.
Surfaces 46a and 46b defining radially outer and inner sides of the
groove 44 are respectively tapered upwardly and outwardly, and
upwardly and inwardly, so that the radial distance between the two
surfaces 46a and 46b increases upwardly from L.sub.2 to L.sub.1 as
shown in FIG. 7. A passage 45 is formed through the planar portion
33 of the movable scroll member 27. One end of the passage 45 is
connected to the compressing space 28 or a delivery portion of the
compressor unit 25 and the other end of the passage 45 is opened to
the high pressure chamber 43 formed in the annular groove 44 of the
annular member 40. An Oldham ring 51 is provided below the planar
portion 33 of the movable scroll member 27, for preventing the
movable scroll member 27 from being rotated around its central
axis.
In the high pressure chamber 43 formed in the annular member 40 are
located an outer seal ring 47a and an inner seal ring 47b for
improving the sealing effect of the high pressure chamber 43. The
seal rings 47a and 47b are provided with tapered surfaces
conforming with the tapered surfaces 46a and 46b defining radially
outer and inner sides of the groove 44, i.e. the chamber 43, so
that the seal rings 47a and 47b are slidingly contactable with the
tapered surfaces 46a and 46b.
Each of the seal rings 47a and 47b is preferably provided with a
cutaway or separated portion 50 as shown in FIG. 8 so as to permit
a required amount of expansion or shrinkage. Furthermore, the seal
rings are made of a resilient material so processed that the outer
ring 47a tends to expand while the inner ring 47b tends to shrink.
As a consequence, when the sealing rings are placed in the high
pressure chamber 43, the rings move upward or downward according to
a gap S formed between the upper surface of the annular member 40
and the lower surface 34 of the movable scroll member 27 along the
tapered surfaces 46a and 46b of the high pressure chamber 43, so
that the gap S is sealed by respective sealing surfaces 48a and 48b
of the seal rings 47a and 47b.
FIGS. 9, 10 and 11 illustrate various examples of the separated
portion 50 formed in each of the seal rings 47a and 47b, among
which FIG. 9 illustrates a separated portion 50 formed obliquely,
FIG. 10 illustrates that formed in stepwise fashion and FIG. 11
illustrates that formed vertically.
Regardless of these configurations of the separated portions,
however, some amount of gas tends to leak out of the high pressure
chamber 43 through the separated portions 50 of the seal rings 47a
and 47b.
According to another example of the seal rings of this invention,
the construction of the separated portion of each of the seal rings
47a and 47b is improved for preventing the leakage of the gas
therethrough. The embodiment will now be described with reference
to FIGS. 12 through 16. In the shown embodiment, for instance,the
outer seal ring 47a is provided with a separated portion 52 formed
into a stepped configuration. More specifically, the seal ring 47a
is separated in the portion 52 such that two end portions 52a and
52b of the seal ring 47a are overlapped with each other to be
slidable in the circumferential direction of the seal ring 47a.
According to a characteristic feature of the embodiment, the end
portions 52a and 52b are disposed to be contactable with each other
along a plane 53 which is extending radially intermediately of the
thickness of the seal ring 47a.
More specifically, when it is assumed that the inner radius of the
seal ring 47a is equal to R.sub.1, the outer radius of the same is
equal to R.sub.2, and the radius of the contact plane 53 is
R.sub.3, the radius R.sub.3 is selected to be
Furthermore, a central angle .theta. formed by a stepped end 53a
and an end edge 53c of the end portion 52a, or by a stepped end 53b
and another end edge 53d of the end portion 52b, is selected to be
less than 10.degree.. In addition, when it is assumed that the
radial thickness of the lowermost part, as viewed in FIG. 12, of
the seal ring 47a is t.sub.1 and the radial thickness of the
uppermost part of the same is t.sub.2, a following relation holds
between t.sub.1 and t.sub.2.
Although the above described relations have been defined with
respect to the outer seal ring 47a, it should be noted that the
same relations are also established with respect to the inner seal
ring 47b.
The operation of the scroll compressor according to this invention
will now be described.
When the movable scroll member 27 in FIG. 6 is rotated, the
compressing space 28 formed between the wraps 26a and 27a of the
stationary scroll member 26 and the movable scroll member 27 is
moved along the wraps 26a and 27a toward the center of the spiroid
while the volume of the compressing space 28 is continuously
reduced. As a consequence, the gas to be compressed supplied from
the gas supplying pipe 30 (FIG. 5) is compressed in the space 28
and delivered from the gas delivering pipe 31. As shown in FIGS. 6
and 7, the movable scroll member 27 is supported by the annular
member 40 through the seal rings 47a and 47b interposed between the
two members 27 and 40. On the other hand, the compressed gas fully
compressed by the scroll compressor or partly compressed in the
compressing space 28 of a compressing stage is supplied through the
passage 45 into the high pressure chamber 43. The pressure Pm thus
created in the high pressure chamber 43 serves to counteract a
downwardly disposed thrusting force created by the internal
pressure of the compressing space 28.
When the pressure Pm overcomes the thrusting force, the movable
scroll member 27 is shifted upward, thus creating gaps of an equal
distance .DELTA.l.sub.2 between the lower surface 34 of the movable
scroll member 27 and the upper surface 41 of the annular member 40
as shown in FIG. 7. As a consequence, the pressing forces applied
to the seal rings 47a and 47b are varied and therefore the outer
seal ring 47a expands radially outwardly by its own resilience to
be moved upwardly along the tapered surface of the wall portions
46a of the annular member 40. Likewise the inner ring 47b shrinks
by its own resilience to be moved upwardly along the tapered
surface of the wall portion 46b of the annular member 40. The
upward movements of the seal rings 47a and 47b permit to seal the
gaps S created by the upward displacement of the movable scroll
member 27. The seal rings 47a and 47b are moved downwardly along
the tapered walls 46a and 46b when the movable scroll member 27 is
displaced downwardly, and in this manner the gaps S are constantly
sealed by the seal rings 47a and 47b regardless of the movement of
the scroll member 27.
Because of the provision of the seal rings 47a and 47b, sealing of
the gaps S provided between the lower surface 34 of the movable
scroll member 27 and the upper surface 41 of the annular member 40
can be assured, and the leaked amount of the gas through the gaps
can be substantially reduced. The reduction of the leaked gas
improves the capacity of the scroll compressor because no
recompression of the leaked gas is required, and since the pressure
of the high pressure chamber 43 can be maintained at a high value,
the downward thrust applied to the movable scroll member 27 can be
substantially reduced.
Tapered angle of either of the surfaces 46a and 46b of the annular
member 40 may be selected arbitrarily so far as the aforementioned
relation L.sub.1 >L.sub.2 is maintained. Furthermore, the
surfaces of the seal rings 47a and 47b slidably contacting with the
tapered surfaces 46a and 46b may be changed into a curved
configuration having a radius of curvature without reducing the
advantageous features of this invention which are summarized as
follows.
(1) Since seal rings having resilience are provided between the
lower surface of the movable scroll member and the annular member,
and the surface of each seal ring contacting with the tapered
surfaces of the annular member is made into a configuration
coinciding with the tapered surfaces of the annular member, the
seal rings can be moved upwardly and downwardly following the
movement of the movable scroll member, and the gaps formed between
the lower surface of the movable scroll member and the walls of the
annular member can be sealed constantly.
(2) Accordingly, the sealing between the movable scroll member and
the annular member can be improved remarkably, and the reduction of
the leakage of the pressurized gas from the high pressure chamber
and the improvement of the capacity of the scroll compressor can be
achieved satisfactorily.
(3) Since the pressure of the high pressure chamber can be
maintained at a high level, the downward thrust applied to the
movable scroll member can be substantially reduced.
FIG. 17 illustrates another embodiment of this invention wherein
the high pressure chamber 43 is provided between the planar portion
33 of the movable scroll member 27 and the frame 23. That is, the
high pressure chamber 43 is provided in the form of an annular
groove 44 provided in the planar portion 33 of the movable scroll
member 27. As described hereinbefore in connection with the former
embodiment, tapered surfaces 46a and 46b are formed along the
radially outside and inside walls defining the annular groove 44,
and outer and inner seal rings 47a and 47b are provided in the
annular groove 44. The outer and inner seal rings 47a and 47b have
tapered surfaces 48a and 48b at portions where the seal rings 47a
and 47b contact with the tapered surfaces 46a and 46b of the
annular groove 44, respectively. A fluid passage 45 is provided
through the planar portion 33 of the movable scroll member 27 for
supplying a pressurized gas obtained from the delivery side of the
scroll compressor into the high pressure chamber 43. The operation
and advantages of this embodiment are quite similar to those
described with respect to the previous embodiment of this invention
shown in FIGS. 6 and 7, and further description thereof is omitted
for avoiding redundancy.
* * * * *